1. Field of the Invention
This invention is related to fuels, especially hydrocarbon fuels, and lubricants, especially lubricating oils, and, more particularly, to a class of anti-oxidant additives having good lubricity, detergency, and rust protection that are the reaction products of acidic organic compounds, such as hydrocarbyl salicylic acids and esters thereof with boron compounds, such as boric acid.
2. Description of Related Art
Metal detergents represent a major source of ash in formulated engine oils. Alkaline earth sulfonates, phenates and salicylates are typically used in modern engine oils to provide detergency and alkaline reserve. Detergents are necessary components of engine oils for both gasoline and diesel engines. Incomplete combustion of the fuel produces soot that can lead to sludge deposits as well as carbon and varnish deposits. In the case of diesel fuel, residual sulfur in the fuel burns in the combustion chamber to produce sulfur derived acids. These acids produce corrosion and corrosive wear in the engine, and they also accelerate the degradation of the oil. Neutral and overbased detergents are introduced into engine oils to neutralize these acidic compounds preventing formation of harmful engine deposits and dramatically increasing engine life.
U.S. Pat. No. 5,330,666 discloses a lubricant oil composition useful for reducing friction in an internal combustion engine which comprises a lubricating oil basestock and an alkoxylated amine salt of a hydrocarbylsalicylic acid of a defined formula.
U.S. Pat. No. 5,688,751 discloses that two-stroke cycle engines can be effectively lubricated by supplying to the engine a mixture of an oil of lubricating viscosity and a hydrocarbyl-substituted hydroxyaromatic carboxylic acid or an ester, unsubstituted amide, hydrocarbyl-substituted amide, ammonium salt, hydrocarbylamine salt, or monovalent metal salt thereof in an amount suitable to reduce piston deposits in said engine. The mixture supplied to the engine contains less than 0.06 percent by weight of divalent metals.
U.S. Pat. No. 5,854,182 discloses the preparation of magnesium borate overbased metallic detergent having magnesium borate uniformally dispersed in an extremely fine particle size by using magnesium alkoxide and boric acid. The preparation involves reacting a neutral sulphonate of an alkaline earth metal with magnesium alkoxide and boric acid under anhydrous conditions in the presence of a dilution solvent followed by distillation to remove alcohol and part of dilution solvent therefrom. The borated mixture is then cooled, filtered to recover magnesium borated metal detergent, which is said to exhibit excellent cleaning and dispersing performance, very good hydrolytic and oxidation stability, and good extreme pressure and antiwear properties.
U.S. Pat. No. 6,174,842 discloses a lubricating oil composition that contains from about 50 to 1000 parts per million of molybdenum from a molybdenum compound that is oil-soluble and substantially free of reactive sulfur, about 1,000 to 20,000 parts per million of a diarylamine, and about 2,000 to 40,000 parts per million of a phenate. This combination of ingredients is said to provide improved oxidation control and improved deposit control to the lubricating oil.
U.S. Pat. No. 6,339,052 discloses a lubricating oil composition for gasoline and diesel internal combustion engines includes a major portion of an oil of lubricating viscosity; from 0.1 to 20.0% w/w of a component A, which is a sulfurized, overbased calcium phenate detergent derived from distilled, hydrogenated cashew nut shell liquid; and from 0.1 to 10.0% w/w of a component B, which is an amine salt of phosphorodithioic acid of a specified formula derived from cashew nut shell liquid.
Provisional Appln. Ser. No. 60/539,590, filed Jan. 29, 2004, discloses a composition comprising the reaction product of an acidic organic compound, a boron compound, and a basic organic compound.